Ok i have 56000 miles on my car. When is a good time to replace my O2 sensors. I not getting any light but my mechanic hooked my car to he computer and it showed my O2 sensors are being lazy. No smart ass remarks please.

I've replaced mine around 80k miles on both W-bodies I have owned (a 98 Intrigue with a 3800 and my 02 Monte). The sensors were working fine in each case, but I thought I might be pushing the limits of their life span and swapped them.

I replaced mines at around 53,000 last year when my cat and tranny went out. Ihad to actually because it seemed as though the sensor was never replaced and it was rusted to the old cat and the thread was messed up.

Ok i have 56000 miles on my car. When is a good time to replace my O2 sensors. I not getting any light but my mechanic hooked my car to he computer and it showed my O2 sensors are being lazy. No smart ass remarks please.

mmm... I was told mine were being "lazy" when I kept getting "bank one, system running rich" and they want $100 to fix it. I didn't think they knew what they were talking about. Instead I put Sea Foam in the tank. Haven't had a problem since. I thought o2 sensors worked or they didn't. Guess lazy is an actual term.

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Last edited by spacewalker404 on Sat Feb 13, 2010 10:00 am; edited 1 time in total

Pretty much. They can get slightly fouled, but the still work the same.

If your doing full exhaust work, sure. Why not replace them. If you're just looking to spend money on the car, spend it else where.

agreed on that ZSPOT if your doing exhaust work and want to change it do it while it's convenient to access it... i did some research and found this little bit of info since our sensor is a lambda style sensor... just my for it

Quote:

Sensor failures

Normally, the lifetime of an unheated sensor is about 30,000 to 50,000 miles (50,000 to 80,000 km). Heated sensor lifetime is typically 100,000 miles (160,000 km). Failure of an unheated sensor is usually caused by the buildup of soot on the ceramic element, which lengthens its response time and may cause total loss of ability to sense oxygen. For heated sensors, normal deposits are burned off during operation and failure occurs due to catalyst depletion, similar to the reason a battery stops producing current. The probe then tends to report lean mixture, the ECU enriches the mixture, the exhaust gets rich with carbon monoxide and hydrocarbons, and the mileage worsens.

Leaded gasoline contaminates the oxygen sensors and catalytic converters. Most oxygen sensors are rated for some service life in the presence of leaded gasoline but sensor life will be shortened to as little as 15,000 miles depending on the lead concentration. Lead-damaged sensors typically have their tips discolored light rusty.

Another common cause of premature failure of lambda probes is contamination of fuel with silicones (used in some sealings and greases) or silicates (used as corrosion inhibitors in some antifreezes). In this case, the deposits on the sensor are colored between shiny white and grainy light gray.

Leaks of oil into the engine may cover the probe tip with an oily black deposit, with associated loss of response.

An overly rich mixture causes buildup of black powdery deposit on the probe. This may be caused by failure of the probe itself, or by a problem elsewhere in the fuel rationing system.

Applying an external voltage to the zirconia sensors, e.g. by checking them with some types of ohmmeter, may damage them.

Pretty much. They can get slightly fouled, but the still work the same.

If your doing full exhaust work, sure. Why not replace them. If you're just looking to spend money on the car, spend it else where.

agreed on that ZSPOT if your doing exhaust work and want to change it do it while it's convenient to access it... i did some research and found this little bit of info since our sensor is a lambda style sensor... just my for it

Quote:

Sensor failures

Normally, the lifetime of an unheated sensor is about 30,000 to 50,000 miles (50,000 to 80,000 km). Heated sensor lifetime is typically 100,000 miles (160,000 km). Failure of an unheated sensor is usually caused by the buildup of soot on the ceramic element, which lengthens its response time and may cause total loss of ability to sense oxygen. For heated sensors, normal deposits are burned off during operation and failure occurs due to catalyst depletion, similar to the reason a battery stops producing current. The probe then tends to report lean mixture, the ECU enriches the mixture, the exhaust gets rich with carbon monoxide and hydrocarbons, and the mileage worsens.

Leaded gasoline contaminates the oxygen sensors and catalytic converters. Most oxygen sensors are rated for some service life in the presence of leaded gasoline but sensor life will be shortened to as little as 15,000 miles depending on the lead concentration. Lead-damaged sensors typically have their tips discolored light rusty.

Another common cause of premature failure of lambda probes is contamination of fuel with silicones (used in some sealings and greases) or silicates (used as corrosion inhibitors in some antifreezes). In this case, the deposits on the sensor are colored between shiny white and grainy light gray.

Leaks of oil into the engine may cover the probe tip with an oily black deposit, with associated loss of response.

An overly rich mixture causes buildup of black powdery deposit on the probe. This may be caused by failure of the probe itself, or by a problem elsewhere in the fuel rationing system.

Applying an external voltage to the zirconia sensors, e.g. by checking them with some types of ohmmeter, may damage them.

yes they will work for sometimes the lifetime of the vehicle but the sensor response time will get slower and slower

Just to clarify, the o2 sensor that's in the downpipe doesn't affect fueling. It's simply there to verify catalyst efficiency. So, if you're replacing the downpipe, replacing the rear o2 sensor isn't going to net you any increase in performance.

If you're replacing the rear exhaust manifold for a ported one, replace the sensor because you'll have to take it out of the manifold anyway.

yes they will work for sometimes the lifetime of the vehicle but the sensor response time will get slower and slower

Yeah, I had my stock one on there up till about 120,000 miles, when my downpipe finally sh*t out on me. Since I was replacing the dp I just did the o2 sensor and cat while I was at it.

that's a long time! lol and whitelightenin good point i was unaware of that cuz i thought it was both of the O2 sensors comparing what was going in the cat and coming out that determined what to adjust the fuel to...

yes they will work for sometimes the lifetime of the vehicle but the sensor response time will get slower and slower

Yeah, I had my stock one on there up till about 120,000 miles, when my downpipe finally sh*t out on me. Since I was replacing the dp I just did the o2 sensor and cat while I was at it.

that's a long time! lol and whitelightenin good point i was unaware of that cuz i thought it was both of the O2 sensors comparing what was going in the cat and coming out that determined what to adjust the fuel to...

Ya it was working fine so I figured why spend money on it until I had too. And I meant to add in that when I changed the rear o2 I did the front as well since I was already at it..